I'd just received my copy of PP through the post so I've read the article and in a nutshell it comes to the following conclusions:
The D200 "feels" more like a pro camera than the 5D.
The metering on the D200 is superior producing better quality detail in highlights.
The 5D has a full frame sensor.
The 5D's image sharpening is better than the D200.
The 5D has produces less noise (when over ISO 1600, at A3, at 200%).
The 5D's battery lasts longer between charges.
Overall, they said the 5D produced slightly better quality images but the D200 won because it was so close to the 5D but for around £600 less.
For me the full frame sensor doesn't seem hugely important. It only seems to make a difference at extreme wide angles. If I want an 18mm shot on the D200 I use a 12mm focal length. I can't imagine I'd ever want to go much wider than that anyway.
Seeing as I know my way around my Nikon I think I'd stick with that when I decide the time has come